Circular knitting machines with a diameter substantially comprised between 7 and 24 inches are known. In recent years, these machines have become widespread as a consequence of the increasing demand for items of clothing, such as for example jerseys, light jerseys, bodysuits, briefs, bras or the like, provided without lateral seams, and as a consequence of the possibility to provide directly on these machines finishing work, such as for example borders, shoulder straps or others, without having to resort to subsequent operations.
In the production of certain items of clothing, such as for example bodysuits and bras, it must be possible to provide three-dimensional shapes aimed at improving the fit and aesthetics of the item of clothing. This requirement is currently met by means of solutions that generally consist in varying the tightness of the knitting and/or in making a set of needles knit for a preset number of courses of knitting while the other needles remain unused, optionally using particularly elastic yarns. However, these refinements do no fully meet the requirements, since a variation in the tightness of the knitting causes a variation in the degree of sheerness of the item of clothing, whereas making a set of needles knit while the other needles are inactive entails trimming the yarn knitted by the needles that are then excluded from knitting, with negative effects on the fit of the item of clothing.